Optical-fibre telecommunications line with protection device for optical amplifiers

摘要

An optical fiber telecommunications system having two terminals interconnected by optical fibers and active-fiber optical amplifiers. Each terminal has an optical telecommunication signal transmitter associated with an optical signal receiver which are interconnected by a protective device which causes the transmitter to be inoperative when its associated receiver does not receive an optical signal. Optical switches are provided at the downstream sides of active-fiber optical amplifiers and are controlled by detecting devices coupled to amplifier outputs, each of which detecting devices opens the associated switch in the absence of a signal having the characteristics, e.g. an alternating component, of the optical telecommunication signal whereby the protective devices are operated.